Polymers of carbon monoxide and olefins, such as ethylene, have been known and available in limited quantities for many years. For example, polyketones are disclosed in Kirk-Othmer Encyclopedia of Chemical Technology, Second Edition, Vol. 12, p. 132, 1967, and in Encyclopedia of Polymer Science and Technology, 1968, Vol. 9, 397-402. It is known that polyketones are prepared by contacting CO and ethylene monomers in the presence of a catalyst. High molecular weight polymers of ethylene which contain small quantities of carbon monoxide can be prepared with the aid of Ziegler catalysts. Low molecular weight polymers of carbon monoxide with ethylene and possibly other olefinically unsaturated hydrocarbons in which all monomer units occur distributed at random within the polymer can be prepared with the aid of radical catalysts such as peroxides. A special class of the polymers of carbon monoxide with ethylene is formed by the high molecular weight linear polymers in which the monomer units occur in alternating order and which polymers consist of units with the formula --CO--(C.sub.2 H.sub.4)--. Such polymers are prepared with the aid of, among others, phosphorus-, arsenic-, antimony-, or cyanogen-containing compounds of palladium, cobalt or nickel as catalysts.
High molecular weight linear alternating polymers of carbon monoxide and ethylene consisting of units of the formula --CO--(C.sub.2 H.sub.4)--, can be prepared by using catalyst compositions comprising:
(a) a compound of a Group VIII metal selected from the group consisting of palladium, cobalt and nickel,
(b) a non-hydrohalogenic acid with a pKa of less than 6, such as paratoluenesulphoncic acid or a metal salt of such an acid, such as a tin or germanium salt, and
(c) a nitrogen bidentate ligand of the general formula ##STR2## wherein X and Y represent similar or different bridging groups, each containing three or four atoms in the bridge at least two of which are carbon atoms.
Application of these catalyst compositions to a monomer mixture which, in addition to carbon monoxide, comprises for example ethylene and one or more alkenically unsaturated hydrocarbons having the general formula C.sub.x H.sub.y leads to the formation of polymers with units of the formula --CO--(C.sub.2 H.sub.4)-- and units of the general formula --CO--(C.sub.x H.sub.y)-- occurring randomly distributed through the polymer chains. The structures of the copolymers and `terpolymers` only differ in that in the case of the `terpolymers` a group --(C.sub.x H.sub.y)-- is encountered at random places in the polymer instead of a --(C.sub.2 H.sub.4)--group.
The activity of catalyst compositions based upon components (a)-(c) is to a great extent dependent on the nature of the component (b) used. Whereas the use of para-toluenesulphonic acid as component (b) yields catalyst compositions with a very attractive activity, this activity is lost when the para-toluenesulphonic acid is replaced by a hydrohalogenic acid, such as hydrochloric acid. The same phenomenon is observed upon replacement of the para-toluenesulphonic acid by a halide of tin or germanium, such as a chloride, as the component (b). This likewise results in a total loss of activity of the catalyst compositions.
The activity of the catalyst compositions based on components (a)-(c) for the polymerization of carbon monoxide with one or more olefinically unsaturated organic compounds can be enhanced by incorporating an organic oxidant into the compositions as component (d). The catalyst compositions based upon components (a)-(d), however, react to the use of a hydrohalogenic acid for component (b) in an analogous way to the catalyst compositions based upon components (a)-(c). In catalyst compositions based upon components (a)-(d) the use of para-toluenesulphonic acid for component (b) results in catalyst compositions having a very attractive activity whereas this activity is lost when the para-toluenesulphonic acid is replaced by a hydrohalogenic acid, such as hydrochloric acid.
In view of the disappointing results obtained with hydrohalogenic acids as component (b) in catalyst compositions based upon components (a)-(c) and in catalyst compositions based upon components (a)-(d), and in view of equally disappointing results from the use of halides of tin or germanium, as component (b) in the catalyst compositions based upon components (a)-(c), it was assumed that halides of tin or germanium were not suitable for use as component (b) in catalyst compositions based upon components (a)-(d).